1. Field of the Invention
This invention relates to improvements in malodorous compositions of matter in conjunction with pressurized air systems to warn persons, such as miners in mines, of danger by smelling the released odor.
2. Prior Art
The malodorous compositions of matter disclosed in U.S. Pat. No. 3,861,350 used nonflammable solvents which caused ozone depletion of the earth's atmosphere. These solvents all contained chlorine, and included trichloro-mono- fluoromethane, trichlorotrifluoroethane, 1,1,1 trichloroethane, methylene chloride, trichloroethylene, and perchloroethylene. Applicants are unaware of any prior art using 1,1,1,2-tetrafluoroethane as a nonflammable solvent for a malodorous composition of matter for use in a warning system, and which is also non-ozone depleting.